Nearly all Eskom power plants persistently exceed air pollution limits stipulated in their licences.

This is according to a new report by US coal plant expert Dr Ranajit Sahu‚ who found that‚ over a 21-month period until December 2017‚ the power utility's coal power plants exceeded its already-weak licence conditions almost 3‚200 times.

The report said this related to all three regulated pollutants for coal plants - namely sulphur dioxide‚ oxides of nitrogen and particulate matter‚ including soot and ash.

Eskom‚ in its response however‚ said its stations generally complied with the conditions of their atmospheric emission licences and the stipulated limits specifically in the period analysed by Sahu.

The analysis was based on Eskom’s own monthly reports of emissions from its coal power plants‚ which were submitted to authorities.

Life After Coal‚ the organisation which commissioned the report‚ said the findings meant that Eskom was continuously endangering health and violating the human rights of millions of people affected by its pollution.

According to the report‚ the offending power stations with the most frequent licence exceedances were Lethabo‚ Matla‚ Matimba‚ and Kriel.

The plants with the highest particulate matter exceedances were Grootvlei (at times as much as 15 times the limit)‚ Kriel (at times as much as six times the limit)‚ and Duvha and Lethabo (at times as much as five times the limit).

Sahu said he reviewed data for 14 of Eskom’s 15 coal-fired stations. All of these plants have six units‚ except Camden‚ with eight units.

Sahu said Kusile was excluded from the analysis as it did not come online before August 2017.

Sahu said his analysis of plant emission exceedances was limited by inconsistent‚ incomplete and unclear reporting.

"When faced with uncertainty‚ I gave the benefit of the doubt to Eskom‚ and so my calculations under-represent the extent of atmospheric emissions licences' exceedances.

"More accurate and comprehensive reporting would significantly enhance government enforcement of atmospheric emissions licences and public scrutiny of power plant compliance‚” Sahu said.

Sahu said from the data‚ it appeared that Eskom treated the limits in its air quality permits as optional targets.

"Whatever pollution control they have is not working‚ or is not being made to work‚" Sahu said.

In its response to Sahu on February 22‚ Eskom denied there were thousands of emission non-compliance events.

"Dr Sahu’s report appears to have a number of errors which significantly overstate the extent of the high emission levels."

Eskom said Sahu’s report reflected a number of daily exceedances‚ and many of these were permitted in terms of the conditions of the atmospheric emissions licences and were therefore not non-compliance.

"Where the authorities have identified significant recurring trends in terms of possible non-compliance they have issued Eskom with pre-compliance notices in terms of the National Environmental Management Act ....Eskom has responded to each of these generally indicating that the high emission levels are not non-compliance to the legislation"” Eskom said.

Sahu recommended that Eskom's data on emissions be made available to the public electronically.

In addition to the emissions data‚ Sahu said reporting should include daily energy production data as well as daily average load levels.

"This would provide the ability and context to evaluate the emissions data; and to be able to normalise the emissions data against capacity and energy production. This too should be provided electronically"

Life After Coal said that Eskom had in January applied for the fourth time for more time to comply with South Africa’s minimum emission standards.

The organisation said‚ based on past reprieves given to Eskom by the department of environmental affairs‚ the power utility operated with many licence conditions that were weaker than the minimum emission standards.

The standards have been law since March 31 2010.

The Life After Coal campaign argued that if Eskom’s coal plants could not comply with the country's already weak emissions standards‚ they should be decommissioned and a plan put in place to support the workers and their families.